1. Field of the Invention
This invention relates to improvements in and relating to steam boiler.
2. Description of the Prior Art
It is known in the art to provide a steam accumulator between a steam boiler and a user in steam using plants or the like for absorbing variations in steam load and thereby preventing the steam load variations from being transmitted directly to the boiler to ensure its stable operation.
The provision of a steam accumulator, however, makes it difficult to detect and record the actual steam load, except the mean value of the steam load which can be detected from the steam flow rate on the outlet or secondary side of the steam accumulator. Therefore, in a case where there is a need for detecting the actual load, it has been the conventional practice to provide a flowmeter on the secondary side. However, since the measurable range of a flowmeter is very narrow, a difficulty is often encountered in correctly measuring the steam flow rate with wide variaty from its maximum to minimum values, coupled with complication of the boiler construction as a whole due to additional piping and wiring.
Although it is possible to employ a flow meter which is constructed in a special form to cover a wide range of measurement, such a flow meter is very costly and often found to be undesirable from an economical point of view.
Further, greater load varuations cause larger variations in the internal pressure of the steam accumulator due to unbalanced flow rates of input and output steam to and from the accumulator, the thus greater variations of the internal pressure make it difficult to control the flow rate of input steam accordingly.